Dry concentrating method and machine therefor



March 25, 1958 R. ca. OSBORNE, JR., ETAL 2,823,016

DRY CONCENTRATING METHOD AND MACH IENE THEREFOR Filed Au 5, 195a 4 sheeis sheet 1 Q 10 .7 RA YMOND G. Oseoeus', 2.0 I I B05527- 0. BOY/(IN, q, mmvroxs. E 1.0 s: 1 g v| BY March 25, 1958 R. G OSBORNE, JR, ET AL DRY CONCENTRATING METHOD AND MACHINE THEREFOR 4 Sheets- Sheet 2 Filed Aug. 3. 1953 ROBERT D- BOY/01v,

ATroe/vsy.

March 25, 1958 R. e. OSBORNE, JR, ETAL 2,823,016

DRY CONCENTRATING METHOD AND MACH [NE THEREFOR Filed Aug. 3,1953 4 She ets-Sheet s I. v RAYMOND G. 058%,

' Boss/er 0. Boy/(w,

INVENTORS Arron/v5 March 25, 1958 R. e. OSBORNE, JR., ETAL 2,823,015

I DRY CONCENTRATING METHOD AND MACHINE THEREFOR Filed Aug. 5, 1953 v 4 Sheets-Sheet 4 .7 BA YMOND 0. 055006;;

RosEer 0. Bo YK/N,

IN V EN TORS.

' Arraewsy.

United States Patent '0 DRY CONCENTRATING METHOD. AND MACHINE 'THERE'FGR Raymond G. :Osborne, .Jr., Los Angeles, and Robert 0. .Boylgin, Glendale, Calif assignors to Raymond Osborne Laboratories, .Inc., Los,Angeles,-Calif,, a corporation of California Application August 3, 1953, Serial No. 372,084

23 Claims. ((31. 209-475) This invention relates to means andsmethods for concentrating or separating selected particles of material such as valuable minerals from a mass of material such as ore which contains various other constituents usually identified as waste or gangue. In particular, the inventionrelates to the working of low grade ores and the separating therefrom of selected minerals by a dry method of operation, that is, "Without the use of Water.

Separation of a selected mineral particle from ,an ore containing other constituents may be accomplished by ntilizing'the diiference .in specific gravity of the selected mineral and the various constituents found with .it in the ore. Separation of such minerals'has"heretofore.been relatively eificiently accomplished in areas where water was readily available. Mineral deposits in such waterplentiful areas could be economically worked by prior proposed separating or concentrating machines.

Such prior separating machines which required the use of water obviously could not be used in areas Where water was not plentiful. Usually mineral depos'itsin Such relatively arid regions could not be worked unless they were of unusually high grade so as to justify costwise the importation and transportation of water thereto. Medium and low grade mineral deposits in arid regions were not worked becausethe costs were prohibitive.

In order to meet the problem of working low grade mineral deposits-in arid regions, various separating machines have been proposed which do not use water.

Such prior machines usually included the use of air .to agitate a crushed or ground mass of ore. machines generally resembled "the separating machines which utilized water and some included a pervions deck with a plurality ofrifile means thereon, the deck 'being agitated by suitable well-known means. Air was blown through the deck at a relatively low pressure and in constant flow for further agitating the material on the deck. Such prior machines were not as eflicient as the separating machines which utilized water.

The primary object of thisinvention is to design and provide a means and method for separating selected particles from a mass of different particles, the various particles having different specific gravity.

Another object of this invention is to disclose aneconornical method for processing .low grade mineral deposits and for deriving a suitable high grade concentrate therefrom which may be transported to other areas for final processing.

Another object of this invention is to design and provide a novel method of separating heavy mineral particles from lighter mineral particles by subjecting said particles to pulsations of air of different superposed frequencies.

A further object of this invention is to design and provide a machine for separating particles of greater specific gravity from particles of "less specific gravity Without the use of water and in which novel utilization is made of air impulses for separating the particles.

Astill furtherobject'of this invention is to design and Such prior a 2,828,016 .Ratented Mar. 2.5.1.958

ice

provide ameans and methodmf separating heavy -particles vof \rninerals from lighter particles wherein =;the separated particles are caused to, fall'through-an upwardly from light particles wherein the separatedparticles are collected andutilizedtopartially close andseal; an ;opening in anair chamber through 'WhiCh I 1PflI1ticlcS fa1 The invention contemplates -a ,novelmeans for agitat inga mass of crushed ,ore by. imparting theret0:.Pll1&ati0ns DTISQIQCtBd ,and adjustahly varied frequencies.

a The invention further conternplates the utilization :of a preselected bedding material or media having $35.31)}?- c'ific gravity lying between the specific gravity ,of ithe selected heavy particle and the specific gravity-hf the light particle .or waste for supporting the .:ore:mass; and which reacts .tocertain of said pulsations of;=air,iin the manner .of a heavy fluid.

:The invention ,further contemplates theuse :Qf :superimposed pulsations of different frequencies to -:agitate crushed ore containing .the selected mineral particles .in such .a manner that selected heavy par i les ar .quickly and .eificiently separated therefrom.

vOther .objects .and advantages of this invention ".Will bereadily apparent from the following description of the drawing in which an ex mplary machine embodying this invention is shown.

.In .the drawings:

Fig. .1 is a diagrammatic sectional view taken .ina

vertical .planepassing through a machine embodying this invention.

Fig. 2 .is a top view taken in -,theiplanes;indicated by line \II1I ,ofFig. 1.

Fig. 3 is anenlarged fragmentarysectional-view of the separating machine shown in Fig.1.

;Fig. 4 is a fragmentary sectional :view ofa discharge gate means employed with the separating machine shown in .Fig. 3..

.lFig. ,5 v is a chart. indicating thereon a curve illustrating a characteristic stroke of the piston means employed in the separating machine shown in Fig. 11..

Fig. ,6 is .asfragmentary, enlarged sectional view-taken in .theplanes indicated by line VI-VI:Qf Fig. 3.

Fig. 7 is a fragmentary sectional 'View taken in :the plane indicated by line VII- VII -of vFig. 6.

Fig. 8 .is an end :viewtaken from ttheleft of Fig. '7.

Fig. 9 is an .end view of the driving means for *the separating machine taken :from the :planes indicated by line IX-IX of Fig. 1.

Fig. 10 is a perspective viewof abellowspiston means employed ,with this invention.

Fig. 11 .is a perspective fragmentary .view of amodification-of the bedding media.

Fig. 12 is a perspective fragmentary view of :a different modification of the bedding media.

Fig. .13 is a fragmentary perspective view of valve means.and ports for the bellows chamber.

As illustrated in Figs. 1 and 2, the separating .machine of this invention may preferably be enclosed within a housing 15 comprising side walls 16,;end .walls 17, .a

roof 18 and an internal partition-wall s19. Thereof may be provided with a vent 21 for discharge of-dust resulting from the separation process and to provide an air .outlet. .Thehousin-g-may be supported upon any suitabletype of floor, andas illustratedtlrezfloor may include a plurality of bins 22 therein for collecting the several concentrates resulting from-theprocess. One-0f the end walls 17 of the buildingmay be provided with a discharge outlet 23 forthe tailings or waste cfromtheore processed.

Means for feeding crushed ore to the separating machine may include a funnel-shaped hopper 25 adapted to receive ore from a suitable supply of ore previously crushed to a selected particle size. In the exemplary embodiment and operation, the ore may be crushed or granulated to a maximum particle size of about 1 inch. The hopper 25 may be continuously fed by any suitable conveyor means. Crushed ore in hopper 25 flows by gravity downwardly through throat 26 therein and to a deflecting spout 27 supported by suitable frame structure of the housing. The spout 27 may be adjustably inclined to a suitable angle so as to discharge crushed ore at a selected rate from throat 26. Discharge of ore may be further controlled by an adjustable gate 28 provided on the lower portion of the hopper adjacent to and above the mouth of the spout 27. r

Means for separating the selected heavy particles from the crushed ore may comprise an exemplary separating machine generally indicated at 36. Before describing in detail theseparating machine 30, it will be understood that the separation process contemplates utilization of the difference in specific gravities of the various particles of ore to be treated. For example, ore containing scheelite which is a source of tungsten has a specific gravity of about 6.0. Scheelite is found'in combination with limestone and quartz which has a specific gravity of about 2.65. While the separating machine is described with respect to the process of separating ore containing scheelite, it is understood that the separating machine is" adapted to be employed for separating various other minerals or any other material in which separation may be based upon the difference in specific gravity characteristics of particles making up the mass of material.

Generally speaking, the separating machine 30 comprises a means for supporting ore containing the selected particles to be separated along a selected path of travel and means for agitating said ore, the means for agitating said ore comprising ameans imparting low frequency range pulsations to the ore mass and means for imparting high frequency range pulsations to the ore mass over the low frequency pulsations. The separating machine includes means for adjustably varying the frequency of the superposed pulsations imparted to the ore mass so as to provide the most effective andefficient type of agitation to the ore mass being processed whereby the selected heavy particles are separated in a quick and efficient manner.

Means for supporting the ore mass may comprise a plurality of material holding receptacles or rectangular baskets 32 arranged in tandem and providing a straight path of travel for flow of the ore mass discharged from the spout 27. The baskets 32 are positioned at decreasing levels, the highest basket 32 being the first basket to receive ore from the feed spout. Each basket may comprise spaced, parallel, end walls 33 connected by spaced transverse side walls 34. As best seen in Fig. 2, the .end walls 33 lie against the side walls 16 of housing 15 so that spilling of crushed ore over end walls 33 is prevented by said housing side walls. The transverse side walls 34 are of substantially the same height and each is provided with a downwardly inclined top edge face 35 directed toward the tailing end of the separating machine to facilitate fiow of material. The end walls 33 and side walls 34 form a rectangular frame for carry.- ing screen means 36 extending across and between bottom margins of said walls 33 and 34. The screen means may be secured to said bottom margins by suitable means, such as screws. The screen means 36 may be of suitable selected mesh depending upon the particle size to which the ore is crushed. The screen mesh may be varied in size for the several baskets depending upon the concentrate desired and the characteristic ore mass being worked. Each basket 32 is removably mounted on the separating machine, the means for securing said basket to the machine being of any suitable type and not shown.

The screen means 36 may support a bedding material 37 of selected depth having a specific gravity lying between the specific gravities of the heavy particles and the lighter waste particles. The bedding material 37 serves as a media which may act with characteristics of a heavy fluid when subjected to high frequency range pulsations as later described. The bedding material 37 may comprise particles of the crushed ore which have a specific gravity lying between the heavy and light particles or it may comprise particles of ore of selected specific gravity placed upon the screen before the introduction of crushed ore to be treated to the machine. The specific gravity of the bedding material in the latter instance may be carefully and accurately selected so as to produce desired separation results.

Other substitutes for the bedding material 37 may comprise a plurality of relatively wide-headed aluminum or lightweight nails (Fig. 11) inserted in the openings of the screen mesh and supported therein by the heads of the nails which are of greater size than the mesh openings. Another suitable bedding material 37 (Fig. 12) may comprise a plurality of loosely interconnected spaced balls of suitable diameter similar to elements of a ball-type chain. The particular function and opera tion of the bedding material will be described later.

The means for agitating an ore mass supported upon the bedding material carried in the plurality of baskets 32 includes a means for imparting low frequency vibrations or pulsations to the mass of material, said low frequency vibrations being in the range of infrasonic or low sonic vibrations. Each basket 32 is supported above an air chamber 45) defined by downwardly converging transverse side walls 41 and 42 and vertical end walls 43 and 44 (Fig. 6). The bottom of chamber 4 may comprise a plurality of downwardly inclined diverging surfaces 45 and 46 provided respectively on suitably shaped spaced polygonal members 47 and 48 respectively extending across and joining the side walls 41 and 42. The surfaces 45 and 46 terminate in top apices which are spaced apart in the same plane, the members 47 and 48 being spaced to provide downwardly directed openings in the bottom wall. These openings lead to a plurality of converging inclined passageways 49 which merge into intermediate downwardly inclined passageways 49a. The several passageways 49 and 49a may be provided by suitable filler plate members secured to and confined between the walls 42 and 81 below the members 47 and 48. The

passageways 49:: may merge at a common point 56 in a means 52 at the end of tube 51.

Each discharge gate means 52 is especially constructed for the purpose of maintaining a selected quantity of concentrate therewithin, as indicated in Fig. 4, so that each air chamber 40 is provided with a substantially closed bottom opening. The discharge gate means 52 may comprise a fixed top cover 53 having downwardly extending side walls 54 and end wall 5 4a received within a bottom spout 55 having upwardly extending side walls 56. The spout 55 is pivotally attached as at 57 to frame structure adjacent to the end of discharge tube 55. and the bottom wall ofrspout 55 is normally inclined at a suitable angle. The spout 55 may be biased toward completely closed position by a suitable spring 58 connected at one end to a side wall of the spout and at its other end to a hook 59 carried by a plate 60. The hook 59 is threadedly adjustable in plate 60 to vary the tension of spring 58 and is held by means of a wing nut 61. The plate 60 carries an inwardly extending deflector plate 62 which limits the discharge of heavy particles collected in the discharge gate means 52. It will be apparent that since cover 53 is fixed in position, and since the spout 55 is biased toward virtually close the bottom end of, the air chamber 40.

When the weight of the particles. in the discharge gate means reaches a selected, amount, the spout 55 will be urged downwardly andawayfrom the cover by the, weight of. said particles to permitidischargeof a selected amount therefrom while at the same time maintaininga selected quantity of material in -the discharge gate means.

Adjacent to each air chamber, may beprovided a bellows-type pump means, said: air pump means including a bellows air pump chamber 65 defined, by one wall 42 of the air chamber and by thecontiguous; bottom surface: of the. inclined wall 41- of the, adjacent. air chamber 40. The bellows pump-chamber 65 may be further defined by vertical end walls 43and 44which extend downwardly from the. ends of the, air chamber 40. A bellows air piston means 66 may betmounted for reciprocal movement on a, transverse pivot shaft 67 mounted in suitable bearing means provided in end, walls. 43 and 44. The shaft 67 lies adjacent to the bottom edge of the cylinder, wal1;42. and is carried by a piston levermeans; 68. The

piston leverv means 68 may comprise; an, integralcasting;

comprisingav transverse partially circular cross-section portion 169 and. an upwardly extending, transversely elongated flat portion 170 integrally connected to, the upper marginal edge of the transversemember. Tfhe; flat: portion 176 may be reinforced by a plurality of spaced intermediate ribs- 1171; integrally merging with the trans? verse portion 169. and end; wallportions 1,72. The intermediate reinforcing. ribs- 171 are nonuniformly spaced? from theend walls 172.and, one of said ribs lies in the planar zone ofa downwar ly extending. lever; portion 173* which affords connection to, a crank arm;99.y Alter.- nate piston, lever; means. 68 are; provided; with lever pordons-173; adjacent to oppositeends. of hetransveltse portion 169:so that in operation the parallel; crank;v arms and the; motor load are substantially uniformly balanced.

The bellows piston means 66 includes a flat rectangularpiston plate 69 secured to the flat portion; 1.7.0.111 any suitable manner as by welding. The; piston plate 69 extends. between the. inner surfaces of end; walls 43.v and 44 and the top'edge'of plate 69 is closely fitted for. reciprocal movement with respect to a: bottom curved surfaceof wall 41. The lower transverse edge of'plate- 69,. may carry a suitable sealing stripfliladapteditoibe compressed between; the-adjacent bottommargin of the cylinder wall 42;=an;d the-piston plate so as to; provide a: seal therefor while thepiston isreciprocated.

The pistonplate; 619) may be; provided along: its upper portion with a plurality. (if-transversely. extending rows of circular air; inlet ports 72 each having aflexiblevalve element 73 of suitable material, suchas rubber composition or; leather. Each valve, element 73. may be secured to the; pistonplate above its; respective port 72: by. a suitable pin; 74. The valve. elements 73. aresecured onthe inner face of the; piston plate 69 so that when the. piston is moving toward closed. position, the valve: elements. 73: will be urged to port closing position-by thecompression of air in the pump chamber, and whilethe piston is movingto open. position, the valve elements will automatically be. moved to open port position: by theinrush of air through said ports.

The air chamber wall 42 is provided with a row of transversely extending air chamber inlet ports 76 arranged above the apices of the surfaces and, 46.. Each port 76 is. likewise provided with a flexible valve element 77 secured to wall 42 on the inner surface thereof in the air. chamber 43, said valve elements 77 being adapted to be, opened when the piston means66 is being closed and to permit discharge of compressed air in thepump cham ber into the air chamber 40. Positive closing. of valve elements 77 is facilitated by depending spring fingers 77a which overlie elements 77 (Fig. 13).

A deflector 7 8v formed of. suitablev plate materiala isseof rotation of the drive wheel is marked on the abscissa.

cured;v beneath at side; wall.- 34 of: each: basket; and. extends. over. thejvalvei elements; andtin spaced relation; thereto so as. to limit. opening of; the valve elements: 77. The. bottom edge. of the deflector p1ate78-is.spacedabove the; apicesformed by the surfaces 45 and 46,-ofi the bottom wall.

The-bellows; piston-means 66in: its open positiontextends into anenlarged open auxiliary chamber. 8,0 formed rearwardlyr of the bellows pumpchamber. 65. and defined:

bya portion ofwall 41: and a downwardly inclined; wall 81 forming, with. the wall 42 a, portionofthe dischargepassageways 49 and 50. The chamber 30 is open teat? mosphere at: the: bottom and. along: the sides thereof so reciprocal pivoted movement may. include a suitable m0."

tor means 85. (Fig.2.), provided: with a drive pulley means Stitch rotating 9. countershaft 8 7,... The. countershaft 8.7. is. provided. with a: centrally located: pulley- 88; whichdrives through. apulleybelt 89, arpulley wheel 90. mount ed axially of the machine. andforwardly. of the. motor The; pulley wheel 90" (Fig. 9,)? may be mounted upon a shaft 91 carried by a-pain of spaced'upstanding standards; 92,. The driving means on: each side, of the pulley wheel. 901is virtually similar and. for brevity the. details of only: oneside isdescribed, in; detaih Each end of shaft:v 9 1 extendsbeyond.the-adjacentstand ard. 92 for mounting. thereon. adrivewheel, 93,. Each. drive: wheel 93:.v carries aneccentric pin 94ito whichmay be pivotally connected one end of drivev crank 95. The:

drive. crank 95 is pivotally connected, at its other end. as; at96 to apair. of parallel connector links 97 which are; pivotally connected; atv their otherend to a. shaft 9,8Tmount A- forwardly exe ed-inupstanding frame. members 98a. tending drive arm 99 may be pivotally connected attone. end to linlc 97 above and. spaced from shaft 98-. The drive arm 99 on one side of themachine may bepivotally connectedas at 100and 101 respectively topiston-means.

eccentric pins 94 disposed at about. 1.80 spaced relation-.

ship; so that the piston means on. the firstzand, third piston. chambers will be in closed position when the piston means; and the second and fourth chambers,- are in open position. The alternate. action of alternate piston means; thereby drive. means.

The particular. action, ofthe piston means 66, should benoted, because the eccentric crank driving meansis so arranged that a sudden, sharp; impulseon blast of air istransmitted from the pump chamber. 65, to the air chamber 40. In Fig; 5 a: curvev is illustrated showing.- the movement. of the piston means ininchesduring one=revolution of the drive wheel. The movement in inches: is: marked on the ordinate axis and the number of degrees.

axis. As. exemplarily illustrated, the, point. 0 maybe consideredthe beginning of the 'backstroke'of the: piston means; from its ultimate closed position in pump chamber 65,. Atv approximately 225' ofrotation, of the drive. wheel the backstroke of. the pistonis, completed andthe forward compression stroke of the piston is begun. Be;- tween about 225 and.270 the piston means moves-forwardly in. the open, auxiliary chamberv 80. At 270 the pistonmeans reaches its maximumlforward speed. and at that point enters the pump chamber- 65; The. rate, of speed continues as. is illustrated: by the substantially straight, downward line formed by the curve. totapproximately. 320? when the rate of; movement; of. the piston. means beginsto decrease and finally-at 3.6.0; the. piston.

assume ,7 means reaches its ultimate, closed position. It will thus be'appar'ent that the maximum rate of forward movement of the piston is provided by the particular drive wheel and linkage arrangement so that'air Compressed in the bellows pump chamber 65 is rapidly, suddenly and sharp- 1y compressed and forcibly ejected through ports 76 into air chamber 40. The ejected blast'of air is deflected downwardly by deflector 78 and then is reflected tipwardly by inclined surfaces and 46. The inclination of these surfaces tends to uniformly distributeth'e air blast over the screen means 36 and a sharp air blow of pulsation is delivered to the ore mass carried on top of the screen means. 7 The pulsations delivered by eachpis ton 66 are preferably in the infrasonic or lowsonic range so that relatively slow, heavy forceful impulses are transmitted and imparted to the ore mass.

Means for further agitating the ore mass by means of high frequency impulses of air may be provided by a motor-drivenblower 110 of well-known make and manufacture and provided with a discharge duct 111 downwardly inclined and mounted exteriorly of the side walls of the housing. The duct 111 forms an exterior manifold 112 which is provided with a plurality of outlets 113 each generally opposite to a basket 32. Each outlet 113 leads to a valved passageway 114 provided with an adjustable valve element 115 of any suitable type, illustrated here as a butterfly valve. Each passageway 114 opens into an air compartment 116 provided in an elongated cylinder 117 having closed ends 118 and 119. "The compartments 116 may be formed by a plurality of longitudinally spaced partitions 120. Extending axially through the cylinder 117 and partitions 120 may be a drive shaft 121 connected at one end to an exteriorly mounted motor 122. Air-chopping member 123 provided with a plurality of curved centrically directed blades 124 may be mounted on shaft 121 for rotation within each compartment.

Opposite blades 124, a discharge port 125 leads to a hollow square section duct 126 extending transversely across air chamber 40 below screen means 32 and slightly above the bottom wall of the air chamber.. The duct 126 is arranged to present upwardly inclined contiguous surfaces 127 to the blast of air entering the chamber 40. The top contiguous surfaces 126 of the duct may be downwardly inclined and may be provided with a plurality of longitudinally spaced discharge ports 127. Each discharge port 127 may be provided with a flexible valve element 128 mounted thereof. To prevent separated particles of the ore mass from falling upon valve ele-.

ments 128, an inverted V-shaped deflector cap 130 may be suitably mounted above and spaced from said ports.

When the blower 11% supplies air to manifold 112 and said air is controllably introduced into compartments 116, the rotating air chopper elements 123 impart relatively high frequency pulsations to the air stream. Thus a high frequency pulsating air stream is ejected through ports 127, into the air chamber 49, and is deflected from the walls of the air chamber 4!) upwardly through the screen means into the ore mass carried thereby. The high frequency air pulsations are transmitted to and impart further agitation to the ore mass, subjecting the ore mass to continuous rapid vibration, the result of which causes the bedding material 37 to act in the nature of a heavy fluid. Thus the agitation of the ore mass by relatively high frequencies, and the superimposed low frequency impulses, causes the heavy particles of a specific gravity greater than the bedding material to be shaken loose from the ore mass and to fall through the bedding material, through the screen, the air chamber, and into the discharge tube. The lighter particles having the specific gravity of, for example 2.65, are blown upwardly from the bedding material, through the ore mass, and are passed over side walls 32 of the baskets onto the ore mass in the adjacent basket. These lighter particles are continually moved down the stepped basket arrangement until they'are discharged as tailings from the discharge duct 23.

In operation, ore which has been crushed or granulated to the selected mesh is fed through the adjustable feed spout 27 to the separating or concentrating machine 30.

The gravity feed of the ore causes the ore to flow in a rial 37 and the ore supported on top thereof is thensuhjected to high frequency air pulsations developed by the blower and the rapidlyrotated air chopping de vice 1.23. The effect of these high frequency pulsations upon the bedding material and upon the ore mass is to shake or rapidly vibrate the same so that it moves and acts in the nature of a heavy fluid. At the same time lower frequency air pulsations developed by the bellow air pump means are imparted and transmitted to the mass of material. The eifect of the closing of each of the bellows piston means 66 is such that a heavy powerful blow or shock is imparted to the quivering ore mass withthe result that the'hea'vier particles of the mass are jolted from association with the remainder of the mass and fall through the bedding material, through the screen means, and into air chamber 49. The heavier particles are then conducted by gravity through the inclined discharge tubes to the discharge gate means. The application of this heavy powerful shock or blow to the ore mass together with the subjection of said mass to the air pulsations of high frequency range produces a very effective separation of the heavy particles from the waste or gangue. The waste particles are conveyed by these air pulsations upwardly through the ore mass and over side walls of the baskets for discharge eventually as tailings from duct 23.

It should be noted that immediately after the deliverance of heavy powerful low frequency air pulsations by the bellow piston means to air chamberdtl the commencerated frequency ranges of pulsations upon the ore mass is maintained at relatively high efficiency by reason of the particular arrangement of the discharge gate means which reduces loss of air through the discharge tubes to a very minimum. It should be particularly noted that the effectiveness of the air pulsations is maintained even while discharging limited quantities of concentrate from the discharge gate device.

In the modification of the bedding material illustrated in .Fig. lZ'each screen means 36' is provided with a plurality of spaced pairs of balls and 176 interconnected by means of a link 177, a' ball or link assembly being provided for each opening in the screen. Preferably the ball and link assemblies are made of a suitable metal coated with a wear resistant surfacing such as chrome or the like. The specific gravity, of the bedding material is particularly selected so that it will be most effective in providing a "ibrating fluid mass through which heavier particles may fall. it is contemplated that when a separating machine embodying this modification is in operation the ball and link assemblies will react to pulsations of selected frequency in such a manner that the top ball 175 will be spaced above the screen means 36 a distance teasers high enough so that. the selected heavy particle, maypass around adjacentballs 175 and downwardly Through the openings in the screen. The lower"ball'1'76fis normally spaced below the mesh a suflicient distance Ito allow passage of such a particle. Obviously theactibn ofthe ball and link assemblies throughout the area of the mesh will not be exactly uniform so that they thereby may afiordffurther agitation of the-mass particularly where the density of the ore mass thereaboveis not" completely uniform.

The exemplary embodiment of this'inventionhas been illustrated having in mind separation of scheelite from an ore mass containinglimestoneand'quartz. Obviously other selected minerals may be' separated"on the machine disclosed. Since other minerals have diiferenfispecific gravities and maybe found inore having waste-on gangue of different specific gravities than those mentioned above, suchvariations in selected --minerals1naybecorrelated to operation of the separatingmachine by varying, for example, t-he specific gravity of'the'bedding material, by changing the particular size of' the ore, by changing the size of meshof: the screen, by progressively decreasing the mesh size of the screen in t heseveral"material holding receptacles, and as i by regulatingsand: controlling the frequency ranges of the superposed low.andihigh'frequency air pulsations so that aimostefiicientaandaeconomicsseparation of=waste and gangue-from=thewaluable minerals is accomplished. The low: frequency :air. pulsations :may be readily varied by changing :the :rate ;of 2 rotation .of-the eccentric drive wheels. The high frequency pulsations may be controlled by the valvedports. -114uand by-zthe. speed rofvrotation :of. shaft 3121 which: carries-tithe aseveral air ,chopping means. flfhese iadjustmentszcancbe '.,1:eadily ma 80 t mmostleflicient-me concentration :of the selected minerals can bra-accomplished.

.lt isunderstood that the volumelofzair displaced from theqbellows pistontchanrbenmay be variedtsmas to-facilitate changes in pulsation afrequency in order to produce desired results on the ore beingprocessed. Suchwolume A pulsation acting ;on the :first baskemfor example, puffs.

orexpands the ,ore mass carried abovethe basket, that is the voids between the discrete .or-e ,particles become larger. The. adjacent basket, not under [the influence of .a pulsation, has its on: mass lying in. arelatively contracted condition. ,The alternate raising and lowering of levels of the ore .mass in adjacent downwardly stepped baskets contribu es to :the movementof the ore mass through .the machine.

It is understood by those skilled in the. art that numerous modifications may be made in the disclosed separating machine which some within the zspirit of ithis invention; and all such modifications and changescoming within the scope of the appended claims tare-embraced thereby.

We claim:

l. in antapparatus tor separating :hea-vy particles from light particles, the combination of: means for :feeding a mass of material including heavy and :light particles along a selected path; a plurality of :material holding receptacles arranged along said path andiat progressively decreasinglevels; each receptacle having abot'tom'screen; means forming an air chamber beneath each of said screens and including downwardlyconvergingside walls and .a means at the bot-tom of said chamber comprising spaced members having. inclined walls extending b tween said side walls and defining a plurality of inclined converging discharge passageways; a common discharge tube beneath each air chamber joined with :said passageways at their point .of. convergence; .a bellows type .airpump positioned adjacenteach .air chamber and including a pump chamber; a bellows piston operable 'in said pump chamber; a valvedrport between saidpump chamber and air chamber for passage of air therethrcugh to said air chamber; driving means for said bcllowspiston arranged to operate at a relatively low frequency for forcibly ejecting sharp impulses of air through said air inlet port to said air chamber to agitate saidmass of material; a valved duct ineachchamber; means connected to each duct for producing relatively high frequency air pulsations to be superposedover said low frequencies in said air chambertoifurtheragitate'said mass ofmaterial; and means to collect andtlischarge heavy particles which'fall through said commondischarge tube so as to virtually seal the-end of said discharge tube during opera'tionwhile affording limited discharge of selected particles.

2. In an apparatus for'separatingheavy particlesfrom light particles, the combination of: means forfceding a mass of'matcrial'including'he-avyand light particlesalong a 'selectedpatma plurality of material holding receptacles arranged along said path and at progressivelydecreasing levels; each receptacle having a bottom screen; means forming an air chamber beneath eachof said screens and including downwardlyconvergingside walls and a means atithe bottomof said chamber comprising spaced members having inclined walls extending between said side walls :and :defining 'a' plurality fof inclined converging discharge passageways; common discharge tube beneath each'air .ch'amberijoined'with.saidzpassageways at their point. ofconvergence; :a :bellows type of air pump positioned adjacent each airchamberand including a. pump chamber; abellows piston-operable in said pump chamber; a valved port between said pump chamber and air chamber for pass-age of air therethrough to said air chambendriving means for said bellows-piston arranged.

' ranged .at progressively decreasing levels along saidrpath;

each basket being. .provide.d with .a-bottom screen means; an air chamber provided beneath each screen means, each air chamber having a valved air inlet port; bellows piston means adjacent to each air chaniber and in communication with the respective air inlet port for the associated chamber; means for driving said bellows piston means at a selected rate to produce air pulsations of low frequencies, said air pulsations being transmitted through said .ports to said air chambers to material in said recaptacles; an .air blower .rneans; a plurality of valved ductsIin said air chambers, each duct being connected with said air blower means; and means associated with said air blower means for producing air pulsations of highfrequency transmitted to said valved ducts and superposed onsaid low frequency pulsations; and discharge means leading from each afir chamber for separated particles of material which fall through said screen means.

4. In a concentrating machine, the combination of: means for directing flow of material of difierent specific grav'ities along'a path;.a'material-holding receptacle in the flow path of the material and including a bottom screen means; an air chamber beneath said screen means and provided with an air inlet port; an air pumping means adjacent to .said air chamber and communicating with the inlet port; means for driving said air pumping means at a selected rate to produce air pulsations of low frequency; a valved duct in said air chamber beneath and mean adjacent to the screen means; means connected to said duct for producing air pulsations of high frequency superimposed on said low frequency pulsations, said high and low frequency air pulsations being transmitted through said air chamber to material in said receptacles for agitation of said material; and discharge means below the air chamber for separated particles of material falling through the screen means.

5. In a concentrating machine, the combination of: means for directing flow of material of different specific gravities along a path; a material-holding receptacle in the fiow path of the material and including a bottom screen means; an air chamber beneath said screen means and provided with an air inlet port; an air pumping means adjacent to said air chamber and communicating with the inlet port; means for driving said air pumping means at a selected rate to produce air pulsations of selected low frequency, said air pulsations being transmitted through said inlet port to said air chamber and to material insaid receptacles; a valved duct extending longitudinally of and beneath the screen means and having inclined surfaces; means connected to said duct to produce high frequency pulsations for transmission through said duct to said air chamber; and discharge means below the air chamber for separated particles of material falling through the screen means.

6. A concentrating machine as claimed in claim wherein said discharge means includes a discharge passageway from said air chamber for flow of separated particles therealong, and discharge gate means at the end of said passageway for collecting a selected amount of said particles to maintain said passageway normally closed while discharging selected quantities of said particles.

7. A machine as defined in claim 5 wherein the discharge means includes a spring-biased, adjustable gate member for limiting discharge of particles from said passageway.

8. A machine as claimed in claim 5 wherein the discharge means includes a plurality of spaced bottom mem bers having downwardly inclined surfaces arranged to deflect low frequency impulses of air received from said inlet port upwardly to the material in said receptacle.

9. In a concentrating machine, the combination of:

means for directing flow of material of different specific gravities along a path; a material-holding receptacle in the flow of the material and including a bottom screen means; an air chamber beneath said screen means and provided with an air inlet port; an air pumping means adjacent to said air chamber and communicating with the inlet port; and means for driving said air pumping means at a selected rate to produce air pulsations of selected low frequency, said air pulsations being transmitted through said inlet port to said air chamber and to material in said receptacles; and means in communication with said air chamber to produce high frequency air pulsations superimposed over said low frequency pulsations.

10. A method of separating heavy particles from light particles, comprising the steps of: feeding a mass of material including heavy and light particles along a selected path of travel; providing and supporting a bedding material of a specific gravity less than the heavier particles and greater than the lighter particles; imparting high frequency pulsations to the bedding material and to the mass of material to be separated whereby said bedding material acts in the nature of heavy fluid; imparting low frequency pulsations to the bedding material and mass of material to cause the heavy particles to drop through said bedding material; and guiding the separated heavy particles to a discharge means.

11. A method of concentrating selected ore particles comprising the steps of: feeding an ore mass ground to selected particle size along a selected path of travel; supporting said ore mass on a bedding material of preselected specific gravity not exceeding the specific gravity of the selected ore particles; imparting pulsations of low frequency to the ore mass and bedding material; simultaneously imparting pulsations of high frequency to the ore mass and bedding material; and guiding particles separated by agitation of said ore mass by said superposed pulsations to a discharge means.

12. In a concentrating machine, the combination of: means for directing flow of material to be treated along a path; a material holding basket aligned with the flow path of the material and provided with bottom screen means; means providing an air chamber beneath said screen means and having an air inlet port; valve means for said port; means limiting opening of said valve means; a bellows piston means adjacent to said air chamber in communication with said inlet port; means for driving said bellows piston means at a selected rate to produce air pulsations of low frequency; air blower means; a valved duct in said air chamber adjacent to and beneath said screen means, said duct being connected to said air blower means in communication therewith; means associated with said air blower means for producing air pulsations of high frequency for transmission to said valve duct for super-imposition on said low frequency pulsations; and discharge means in communication with said air chamber for separating particles of material.

13. In a concentrating machine, the combination of: means for directing flow of material to be treated along a path; a material holding basket aligned with the flow path of the material and provided with bottom screen means; means providing an airchamber beneath said screen means and having an air inlet port; valve means for said port; a bellows piston means adjacent to said air chamber in communication with said inlet port; means for driving said bellows piston means at a selected rate to produce air pulsations of low frequency; air blower means; a valved duct in said air chamber adjacent to and beneath said screen means, said duct being connected to 'said air blower means in communication therewith; means material holding basket provided with bottom screen means; means providing an air chamber beneath and coextensive with said basket; downwardly converging side walls defining sides of said chamber; valved ports in one of said side walls adjacent to and beneath the screen means; deflector means inclined downwardly over said ports and in spaced relation thereto; a bellows chamber adjacent to said one side wall in communicationwith said port; a valved bellows piston operable in said chamber to produce low frequency pulsations of air for transmission through said ports into said chamber; means extending beneath and adjacent to said screen means for transmitting high frequency air pulsations to said chamber; means connected to said means in said chamber for producing high frequency air pulsations; and discharge means in communication with said air chamber for guiding separated particles of material Which fall through said screen means.

15. In a concentrating machine, the combination of: means for directing flow of material to be treated along a path longitudinally of the machine; a plurality of material-holding receptacles aligned with the fiow path of the material and arranged transversely thereof at progressively decreasing levels along said path; each receptacle being provided with a screen means; means providing an air chamber beneath each screen means and including a wall having a valved port in communication with said chamber; a bellows piston means adjacent to each air chamber and including a bellows chamber having one side thereof defined by said ported wall, and a bellows piston pivotally mounted adjacent one end of said Wall, said bellows piston having a plurality of valved bellows ports; means for driving said bellows piston at a selected rate to produce air pulsations of low frequencies transmitted through said valved ports leading to said air chambers and to material in said receptacles; and discharge means leading from each air chamber for separated particles of material which fall through said screen means.

16. A concentrating machine as stated in claim 15 including means in each air chamber to transmit pulsations of high frequency to said air chambers and to material in said receptacles.

17. A concentrating machine as stated in claim 16 in cluding means providing pulsations of high frequency in communication with said transmitting means in said chambers.

18. In a dry concentrating machine, the combination of: means for directing flow of material to be separated along a selected path; a material-holding receptacle in the flow path of the material to be separated and including a screen means; means providing an air chamber With an inlet port below the screen means; means for producing pulsations of low frequency in communication with the inlet port; means for producing pulsations of high frequency in communication with said chamber; said high and low frequency pulsations being transmitted through the air chamber to the material in said receptacle for agitation of said material; and discharge means for separated particles falling through the screen means.

19. In a concentrating machine as stated in claim 18 including a bedding material carried on said screen means.

20. In a concentrating machine as stated in claim 18 including a bedding material carried on said screen means, said bedding material having a specific gravity not exceeding the specific gravity of material to be separated.

21. In a concentrating machine as stated in claim 18 including bedding material comprising a plurality of ball and link assemblies cooperable with the screen means.

22. A dry method of separating heavy particles. from light particles, comprising the steps of: feeding dry material including heavy and light particles along a selected path of travel onto a dry bedding material; imparting pulsations of high frequency to the bedding material and to said particles; simultaneously imparting pulsations of low frequency to the bedding material and to said particles; and collecting the particles separated thereby.

23. A dry method of separating heavy particles from light particles, comprising the steps of: feeding a dry mass of material including heavy and light particles along a selected path of travel onto a bedding material of specific gravity greater than the light particles; subjecting said mass of material and said bedding material to pulsations of high frequency; subjecting said mass of material and said bedding material simultaneously to pulsations of low frequency to cause the heavy particles to drop through said bedding material; and collecting the separated heavy particles.

References Cited in the file of this patent UNITED STATES PATENTS 686,741 Krom Nov. 19, 1901 1,016,680 Edgar Feb. 6, 1912 1,787,340 Davis Dec. 30, 1930 1,837,438 Wolf Dec. 22, 1931 2,040,503 Saxe May 12, 1936 2,148,067 Fuller Feb. 21, 1939 2,344,094 Kraut Mar. 14, 1944 

